import math

inp = input().split(' ')
a = float(inp[0])
b = float(inp[1])

def fun(x):
    if x!=0:
        return math.sin(x)/x
    else:
        return 1

ans=0

k=[7/90,16/45,2/15,16/45,7/90]

start=a
delta=(b-a)/4
j=0
for i in k:
    ans+=i*fun(start+j*delta)
    j+=1
ans*=(b-a)

print("%.5f"%ans)